The source of lithium in the soil at surface is hopefully...

The source of lithium in the soil at surface is hopefully spodumene pegmatites at depth. In reality it can't be anything else. Erosion of the buried pegmatites occurs from water but also from other forces such as temperature changes (expansion and contraction of parent rock), ice, wind, water and vegetation. The result of these forces acting on the buried pegmatites over eons is lithium at the surface. Just like the soil in your own backyard originates from the weathering of buried bedrock.

Every exploration manager has more theories on how to find the buried pegmatites than he has money to fully explore these theories. This is why Duggers is narrowing the number of inchoate theories and options by undertaking the soil analysis on an ever-tightening grid. It's a bit like following the Iliad to find Troy. The premise is the higher lithium concentrations in the soil sit directly above the buried spodumene below. The theory can be further refined with magnetics and other survey work. This is in essence what Liontown did to find Kathleen Valley. I'm not saying we have another KV on our hands but the soil samples show we likely have spodumene buried below. How much and at what grade are the unknowns and why we're all here. All in my opinion.